Receivers used in services where the received signals are intermittent have a problem in detecting when the receiver's chain of equipment (e.g. antenna, cabling, connectors, receiver, power, etc.) has an impairment or fault.
In RADAR applications, if a response is not detected to an interrogation signal, the reason behind the lack of response remains: is it because there are no targets or is it because the receiver chain of equipment is impaired or faulty?
In two-way radio applications, if a response is not received from a called party, the question is the same: is it because the called party is not responding or is it because the receiver chain is impaired or faulty?
For one-way (receive-only) radio applications, if a signal is not received within a pre-specified period a similar question arises: is it because there is no information available or is it because the receiver chain of equipment is impaired or faulty?
In PRIMARY or AREA SURVEILLANCE RADAR, sometimes use is made of signals reflecting permanent echoes to verify the operation of the receiver chain of equipment. However, the use of such methods are only available if these permanent echoes are available and detectable within the RADAR coverage area. However, if the RADAR uses Moving Target Indication, Moving Target Detection or Doppler Processing filters, these (stationary) permanent echoes are eliminated from the received signals.
In Secondary Surveillance Radar and Automatic Dependent Surveillance-Broadcast, use is sometimes made of a test transponder, sometimes called a Position Adjustable Range Reference Orientation Transponder or PARROT. This test transponder needs to be placed at a distance from the receiver so it requires real estate and reliable power. It usually also requires reliable communications for it to be monitored by remote maintenance monitoring.
Based on the above, there is therefore a need for a solution that can be easily deployed, does not require real estate, and which can test and determined whether RF signal receiving equipment is working properly.